In most cases, the natural colour of teeth ranges in light grey and yellow shades. Teeth naturally darken with age. Stains may result from the use of tobacco products, and the consumption of certain foods or drinks. Many people want a brighter smile, and many options to whiten your teeth are now available. Most bleaching products are peroxide-based and are thus capable of altering the colour of the tooth. After the dentist treats all decay areas in your teeth, stronger bleaches can be used to achieve better results.